You're dehydrated and so is your skin
Contrary to what you may think, getting your daily dose of water directly affects the way your skin appears. Without the proper amount of moisture, your skin will look dull. The problem is deeper than you can even fathom, being under-hydrated causes the skin to have a decrease in thickness -- like a deflated balloon. Not only will you not shine and look radiant but you will also look sallow. So next time you want to skip out on those eight cups of water a day, think again.
Dead skin cells are a thing
If your skin has that ashy tint to it, it could probably be that you have a layer of dead skin cells sitting on top of what would be amazingly dewy, fresh skin. Think of dead skin cell buildup like dust. If you don't wipe it clean, it will stay dingy until you decide to. This is also why it's important to clean your face every single day, even if you're not wearing makeup. If that doesn't help, use a gentle exfoliator to sloth off the dead cells.
I think in almost every one of our articles there is a mention of moisturizing. It is that important. If you don't moisturize your skin, it will not be adequately hydrated and if it's not adequately hydrated, it will look unhappy. Moisturizer provides your skin many benefits including turning your dull skin into happy, healthy looking skin. Remember to apply your moisturizer in upward strokes to boost blood circulation and stimulate the cells around your face and neck. This will bring oxygen to the surface giving you a nourished look.
Life is stressful
The age old answer is yes, stress does age you. When you're stressed your body releases cortisol which is a hormone that breaks down collagen. Collagen is what keeps your skin looking plump and youthful. Being told to relax is definitely not the solution here but if you try a quick facial massage with a jade or rose quartz roller, it helps increase the blood flow to your skin which will help boost collagen and make your skin look more radiant.
Poor or no diet and exercise
The saying goes "you are what you eat" and there's a reason why, especially when it comes to your skins health. What you put in your body is reflected in your complexion, so don't expect to under-nourish your body and have great skin. A diet filled with sugar is going to wreak havoc on your skin, as well as your mood, weight, and brain function. Same goes for exercise but exercise will boost more than just your muscles. Aerobic activity enhances circulation to the skin which is why you usually have that gorgeous flush look when you finish a fulfilling workout.